ABSTRACT Spinocerebellar ataxia type 1 (SCA1) is a trinucleotide repeat disorder with a variable clinical phenotype consisting of ataxia, dysarthria, and peripheral neuropathy, but no primary muscle involvement. Another trinucleotide repeat disorder, oculopharyngeal muscular dystrophy (OPMD), is a progressive myopathic disorder characterized predominantly by dysarthria, dysphagia, ptosis, and proximal weakness. We describe the clinical and electrophysiologic, features of a patient with genetically confirmed SCA1 with an OPMD-like presentation. The findings of a peripheral neuropathy without myopathy on electrodiagnostic testing are useful to help in differentiation of the disorders and are supportive of SCA1. This case illustrates that the differential diagnosis of patients with dysphagia and dysarthria should be expanded to include SCA1.
Objective: In patients with symptomatic diabetic polyneuropathy, is oral alpha-lipoic acid (ALA) effective in improving neuropathic symptoms compared with placebo? Methods: The question was addressed with a structured evidence-based clinical neurologic practice review via videoconferencing between 3 academic institutions. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarians, and clinical content experts. A critically appraised topic format was employed, with a clinical scenario, structured question, search strategy, appraisal, results, summary of evidence, commentary, and bottom-line conclusions. Results: A single modestly valid randomized controlled trial demonstrated that oral ALA in doses of 600 mg, 1200 mg, and 1800 mg was effective in reducing neuropathic symptoms of diabetic distal symmetric polyneuropathy (DSP) at 5 weeks, as assessed by the Total Symptom Score (≥50% reduction), with number needed to treat (NNT) (95% CI) of 2.7 (1.8 to 5.8), 4.1 (2.3 to 20.2), and 3.2 (2.0 to 8.6), respectively. Adverse events, including nausea, vomiting, and vertigo, were identified but occurred most frequently with ALA doses of 1200 mg and 1800 mg. Overall, treatment emergent adverse events for ALA 600 mg were not significantly different than placebo, but ALA 1200 mg and 1800 mg had number needed to harm (95% CI) of 4.5 (2.4 to 31.0) and 3.0 (1.9 to 7.1), respectively. Conclusion: Oral ALA may improve neuropathic symptoms in diabetic DSP. A single modestly valid RCT demonstrated that 600 mg was an effective and well-tolerated dose, with NNT 2.7 to significantly reduce neuropathic pain symptoms over a 5-week period. ALA's role and place in an algorithm among other commonly prescribed oral treatments for symptomatic relief of neuropathic pain in diabetic DSP remains unclear.
Complex repetitive discharges (CRDs) are incompletely understood needle electromyography (EMG) waveforms seen in both myopathic and neurogenic disorders including radiculopathies. This study aimed to clarify the significance of CRDs in patients with radiculopathies.This case-control study randomly identified 100 patients with needle EMG evidence of radiculopathy demonstrating at least one CRD in the electrodiagnostically involved myotome between January 2017 and January 2022. These patients were compared with 100 randomly selected patients with EMG evidence of radiculopathy without CRDs controlled for sex, age at EMG testing, and affected nerve root segment. Patient clinical symptoms, neurologic examination, EMG features, and imaging were analyzed. A paired sample t-test for categorial data and χ2 test for nonparametric data were used for statistical analysis with significance defined as P < 0.05.Patients with radiculopathies with CRDs had longer disease duration averaging 59 months (range 1-480) compared with patients with radiculopathies without CRDs averaging 26 months (range 1-192, P < 0.01). Clinical symptoms of paresthesias and weakness were both significantly more common in patients with radiculopathies with CRDs than those without CRDs (P < 0.01 and 0.01, respectively). Needle EMG demonstrated a greater average number of muscles with neurogenic motor unit potentials per radiculopathy in patients with radiculopathies with CRDs compared with those without CRDs. Imaging studies of patients with radiculopathies with CRDs were more likely to reveal evidence of nerve root compression (P < 0.01).The presence of CRDs in patients with radiculopathies is consistent with clinically more symptomatic radiculopathies and a longer duration of nerve root compromise.
The authors report four patients with upper thoracic radiculopathies presenting with axilla pain. All patients had a malignancy affecting the upper thoracic nerve roots. Electrodiagnostic testing demonstrated abnormalities in the upper thoracic nerve root distribution; imaging demonstrated neoplasms. Pain in the armpit that is severe or progressive may be indicative of a malignant pathology, and evaluation should target the upper thoracic roots.
April 22, 2018April 10, 2018Free AccessExpanding the Phenotype of SEPT9 Gene Mutations in Hereditary Neuralgic Amyotrophy: Slowly Progressive and Painless Bilateral Brachial Plexopathies (P1.459)Rocio Vazquez Do Campo, Eric Goldstein, and Devon RubinAuthors Info & AffiliationsApril 10, 2018 issue90 (15_supplement)https://doi.org/10.1212/WNL.90.15_supplement.P1.459 Letters to the Editor
Clinical neurophysiology testing primarily assesses and characterizes neurological disease. Selection of appropriate studies for the problem of an individual patient requires a careful clinical evaluation to determine possible causes of the patient’s symptoms. The approach to testing can be assisted by deciding which structures are likely to be involved. For example, motor and sensory symptoms are best assessed using the different methods of motor and sensory NCS. Deciding which neurophysiological measures to apply in peripheral disorders is sometimes assisted by applying guideline protocols based on the patient’s clinical findings and what is found during testing. Although a clinical neurophysiological assessment rarely provides evidence for a specific diagnosis, it can provide valuable information about the severity, progression, and prognosis of the disease. This chapter reviews the clinical application of neurophysiological tests, particularly nerve conduction studies and needle EMG, in the assessment of patients with a variety of neuromuscular complaints.
Spontaneously generated or stimulus-induced electrical signals from neural tissue in the central, peripheral, and autonomic systems are recorded and displayed as waveforms through digital equipment in neurophysiological testing. The waveforms recorded in clinical neurophysiology are divided into continuous waveforms and intermittent, discrete waveforms or events. Continuous waveforms are described by their frequency components, amplitudes, and distributions. Discrete waveforms are described by their individual amplitudes, durations, and configurations as well as by their patterns of occurrence and distribution. Changes in each of these waveform parameters may occur in diseases, and discrete waveforms themselves may be abnormal. Artifacts can alter all of the variables used to describe the continuous and discrete waveforms recorded in clinical neurophysiology. This chapter reviews concepts related to the various waveforms recorded in clinical neurophysiology.
